PC Hardware in a Nutshell, 3rd Edition

Cable Guidelines

Keep the following issues in mind when you need to buy or build a cable:

• Buy the cable if you can. Any cable you need is probably a standard item, and will be cheaper and better than one you build. If you need an unusual pinout, order a custom cable from Black Box, DataComm Warehouse, or another company that produces cables to order.

• Use the shortest cable possible for more reliable connections, particularly at high speeds. If you need a long cable, buy a high-grade one made with low-capacitance wire.

• Don’t judge cables by appearance. Mass-produced cables appear similar, but vary in quality. Custom-built cables are usually of high quality, and priced accordingly. You’ll get no more than you pay for, and sometimes less.

• Don’t assume that a cable connects every pin that appears on the connector. Mass-produced cables usually have pins in each position, while custom-built cables often have pins only in the positions that are actually connected. Nearly any DB9 serial cable connects all nine pins, but cables with two DB25s may have anything from three to 25 pins connected, with nine and 25 wire connections most common. Any decent mass-produced cable lists the number of wires and how they are connected on the packaging, and sometimes on the connectors.